All too late for Arsenal?

Arsenal had lost three straight home games in all competitions going into the match, but this was a routine win as they closed the gap to leaders Leicester to eight points.

Arsene Wenger's side still need an unlikely collapse from both the Foxes and second-placed Tottenham to have any hope of securing the league title, while tough trips to West Ham and Manchester City await in their remaining seven games.

Nigerian youngster Iwobi showed his potential with a pacy performance that threatened the Watford defence throughout. He netted the second goal as well as rattling the crossbar with a curling effort.

Iwobi, Sanchez and Mesut Ozil all had fine games - but were given time and space by a lethargic Watford side and by the protection offered in the middle of the park by Mohamed Elneny, who controlled the contest with a match-high 127 passes, 96% of which found a team-mate.

The Egyptian also had time to make three tackles and two interceptions, but Arsenal's upswing in form might have come too late in the season. The damage may have already been done as they picked up just their fourth win in their past 11 league games.

Watford have problems but should be fine

Watford have now won only twice in 13 league games, which includes five defeats in their last six.

Despite dumping Arsenal out of the FA Cup with a brilliant performance last month, this showing was feeble from the first whistle.

They went behind early and barely threatened over 90 minutes. managing just two shots on target, both of which fell to skipper Troy Deeney.

The Hornets were seventh at Christmas but have since fallen to 14th in the table, 11 points above the relegation zone. They have goalkeeper Gomes to thank for avoiding an even more comprehensive drubbing here, as the Brazilian made superb stops from Iwobi and Sanchez.

With Aston Villa all but down, though, Watford's excellent first half of the season should be enough to preserve their status in the top flight.

Man of the match - Alex Iwobi

One goal, one shot against the crossbar and forcing Heurelho Gomes into a full-stretch save - 19-year-old Iwobi showed his potential with a classy performance

What they said:

Arsenal forward Alex Iwobi: "It's crazy, a mad feeling. When you're young, you dream of this and this is like a dream come true, winning with this team. Winning the title would be amazing but we're taking each game as it comes, game by game, and we will see where we end up come the end of the season."

Arsenal manager Arsene Wenger: "I am very happy because it was a good performance. We scored goals and didn't concede, and kept the game having a good flow even at 3-0 up.

"I am pleased with Alex Iwobi's talent but even more with his attitude and his willingness to learn and to contribute with his teamwork."

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Arsenal 4-0 Watford: Early goal made it difficult - Quique Flores

Watford boss Quique Sanchez Flores: "It is the first time we have conceded four goals and we are not happy with that. We looked light and soft, and that is not our style. We need to finish the season in the best way possible, because the players have worked very hard all season. I can't be angry with the team because I am the team, and I cannot be angry with myself."

What's next?

Arsenal travel to West Ham next Saturday (kick-off 12:45 BST), while Watford host Everton on the same day (15:00 BST).

The stats you need to know:

Alex Iwobi scored in back to back games for Arsenal (two goals) after failing to score in any of his 13 previous appearances in all competitions

Alexis Sanchez scored and assisted in the same Premier League game for the first time since April 2015, when he did so against Liverpool

Hector Bellerin has been involved in four goals in his past three Premier League games (one goal, three assists)

Only Crystal Palace (three) have gained fewer points than the Hornets in 2016 (eight)